How to scroll to top of long ScrollView layout?

问题:

For part of my app, the user is presented with a list of names and is asked to group them as they see fit.

(Note, the ListView code was copied verbatim from the Android Views tutorial. I haven't yet customized it to my needs, I'm just trying to figure out how to make this work.)

The basic layout is a LinearLayout, containing a ScrollView (called "groupsScrollView" in the code below), containing a RelativeLayout. I have some buttons and text, and then my ListView beneath that, which displays the list of names. All this is taller than the visible screen area, so the user is allowed to scroll vertically to see it all.

This all works beautifully, except when the page loads it is always pre-scrolled to the top of my ListView - in the middle of the page. The text and buttons I've created that tell the user what to do are not visible.

I can grab the screen and scroll up, that works just fine, but I'd like the screen to load having already been scrolled to the top. The user shouldn't have to scroll UP to see the top of a freshly loaded page. But everything I've tried to programmatically scroll to the top of the screen has failed.

Here's my onCreate method:

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.groups);

    mainScrollView = (ScrollView)findViewById(R.id.groupsScrollView);

    //get the Bundle out of the Intent...
    Bundle extras = getIntent().getExtras();
    mNames = extras.getStringArray("mNames");

    setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item, mNames));

    ListView lv = getListView();
    lv.setTextFilterEnabled(true);

    //This is the line I'm having issues with
    mainScrollView.pageScroll(View.FOCUS_UP);

    lv.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view,
            int position, long id) {
          // When clicked, show a toast with the TextView text
          Toast.makeText(getApplicationContext(), ((TextView) view).getText(),
              Toast.LENGTH_SHORT).show();
        }
      });
}

The line "mainScrollView.pageScroll(View.FOCUS_UP); is the problem. It doesn't cause an error, but it doesn't seem to do anything. I've tried scrollTo(0,0), scrollDirection(View.FOCUS_UP), and everything else I can think of.

Since I don't get an error I have to assume that these scroll commands are actually working, but that they're scrolling to the top of the ListView, rather than the top of the ScrollView or RelativeLayout that contains it. This seems to be confirmed by Google's own description of the scrollTo(int x, int y) method where they say "This version also clamps the scrolling to the bounds of our child.".

So to make a long question even longer, how do I load a bunch of views on the screen contained within a ScrollView, and then programmatically scroll the whole thing to the top of the page so the user can interact with it?

Thanks!

回答1:

Try

mainScrollView.fullScroll(ScrollView.FOCUS_UP);

it should work.

回答2:

Had the same issue, probably some kind of bug.

Even the fullScroll(ScrollView.FOCUS_UP) from the other answer didn't work.
Only thing that worked for me was calling scroll_view.smoothScrollTo(0,0) right after the dialog is shown.

回答3:

i had the same problem and this fixed it. Hope it helps you.

listView.setFocusable(false);

回答4:

scrollViewObject.fullScroll(ScrollView.FOCUS_UP) this works fine,but only the problem with this line is that, when data is populating in scrollViewObject,you call immediately. You have to wait for some milliseconds until data is populated. Try this code:

    scrollViewObject.postDelayed(new Runnable() {
    @Override
    public void run() {
        scroll.fullScroll(ScrollView.FOCUS_UP);
    }
}, 600);

OR

 scrollViewObject.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        scrollViewObject.getViewTreeObserver().removeOnGlobalLayoutListene‌​r(this);
        scrollViewObject.fullScroll(View.FOCUS_UP);
    }
});

回答5:

The main problem to all these valid solutions is that you are trying to move up the scroll when it isn't drawn on screen yet.

You need to wait until scroll view is on screen, then move it to up with any of these solutions. This is better solution than a postdelay, because you don't mind about the delay.

    // Wait until my scrollView is ready
    scrollView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            // Ready, move up
            scrollView.fullScroll(View.FOCUS_UP);
        }
    });

回答6:

Very easy

    ScrollView scroll = (ScrollView) findViewById(R.id.addresses_scroll);
    scroll.setFocusableInTouchMode(true);
    scroll.setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);

回答7:

I faced Same Problem When i am using Scrollview inside View Flipper or Dialog that case scrollViewObject.fullScroll(ScrollView.FOCUS_UP) returns false so that case scrollViewObject.smoothScrollTo(0, 0) is Worked for me

Scroll Focus Top

回答8:

 final ScrollView scrollview = (ScrollView)findViewById(R.id.selected_place_layout_scrollview);

         scrollview.post(new Runnable() { 
                public void run() { 
                    scrollview.scrollTo(0, 0); 
                } 
            }); 

回答9:

runOnUiThread( new Runnable(){
   @Override
   public void run(){
      mainScrollView.fullScroll(ScrollView.FOCUS_UP);
   }
}

回答10:

This is force scroll for scrollview :

            scrollView.post(new Runnable() {
                @Override
                public void run() {
                    scrollView.scrollTo(0, 0);
                    scrollView.pageScroll(View.FOCUS_UP);
                    scrollView.smoothScrollTo(0,0);
                }
            });

回答11:

scrollView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        // Ready, move up
        scrollView.fullScroll(View.FOCUS_UP);
    }
});

回答12:

This is worked for me

scroll_view.smoothScrollTo(0,0); // scroll to top of screen

回答13:

@SuppressWarnings({ "deprecation", "unchecked" })
public void swipeTopToBottom(AppiumDriver<MobileElement> driver) 
                    throws InterruptedException {
       Dimension dimensions = driver.manage().window().getSize();
        Double screenHeightStart = dimensions.getHeight() * 0.30;
        int scrollStart = screenHeightStart.intValue();
        System.out.println("s="+scrollStart);
        Double screenHeightEnd = dimensions.getHeight()*0.90;
        int scrollEnd = screenHeightEnd.intValue();
        driver.swipe(0,scrollStart,0,scrollEnd,2000);
        CommonUtils.threadWait(driver, 3000);
    }